<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>svg</title>
</head>
<style>
    * {
        margin: 0;
        padding: 0;
    }

    .box {
        width: 100vw;
        height: 100vh;
        border: 1px solid #000;
    }
</style>

<body>
    <div class="box">
        <svg xmlns="http://www.w3.org/2000/svg" version="1.1" style="width: 100%;height: 100%;">
            <circle cx="50" cy="50" r="40" stroke="#ccc" stroke-width="6" fill="green" />
            <rect width="200" height="100" x="200" y="200"
                style="fill:rgb(26, 255, 0);stroke-width:6;stroke:rgb(206, 20, 20)" opacity="0.3" />

            <circle cx="300" cy="70" r="50" stroke="black" stroke-width="2" fill="red" />

        </svg>


    </div>
</body>

</html>